Effect of hydrocolloids on functional properties of navy bean starch

Abstract

The effects of hydrocolloid replacement on the pasting properties of navy bean starch and on the properties of navy bean starch gels were studied. Navy bean starch was isolated, and blends were prepared with β‐glucan, guar gum, pectin, and xanthan gum solutions. The total solids concentration was maintained at 8%, and starch was replaced with 0.2, 0.4, and 0.6% of each hydrocolloid. Guar gum led to an increase in the peak viscosity during pasting as well as an increase in the final viscosity. Each of the other hydrocolloids decreased the peak and final viscosities, with xanthan gum causing the largest decrease. β‐Glucan and pectin reduced the water solubility and absorption indices at low temperatures, and each hydrocolloid reduced the enthalpy of gelatinization. Gels were also prepared at each concentration, and the storage modulus decreased for xanthan gum, while both guar gum and xanthan gum gels had higher loss tangents. The hardness of the gels decreased for guar gum, and much more for xanthan gum. Each of the hydrocolloids improved the freeze‐thaw stability, with guar gum having the largest effect. These results show the possibility of improving navy bean starch and flour properties through the addition of hydrocolloids.